Cis-retaining selective hydrogenation of vegetable oils



United States Patent 3,542,821 CIS-RETAINING SELECTIVE HYDROGENATION 0F VEGETABLE OILS Edwin N. Frankel, Peoria, 111., assignor to the United States of America as represented by the Secretary of Agriculture t No Drawing. Filed Aug. 30, 1968, Ser. No. 756,423 Int. Cl. Cllc 3/12 US. Cl. 260-409 3 Claims ABSTRACT on THE DISCLOSURE Arene chromium carbonyl complexes under specified conditions very selectively catalyze the hydrogenation of only the linolenate and linoleate constituents of vegetable oils or their methyl esters without also catalyzing the reduction of the oleate to stearate. Most importantly, the catalysts provide extraordinarily limited extents of double bond isomerization, and are unique in their ability to retain or direct the resulting residual ethylenically unsaturated carbon atoms almost exclusively in the original type cis configuration, thus permitting the production from soybean or saffiower oils of stable salad oils in which the virtual absence of trans double bonds and a practically unchanged stearate content enable the nonwinterized oils to be refrigerated without clouding. Saponification of the so hydrogenated soybean or safllower oil or mixed methyl esters further provides a predominantly cis oleic acid material that closely approximates the commercial 75-85 percent oleic acid produced after the fractionation of animal fats.

A nonexclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

BACKGROUND OF THE INVENTION Extensive industrial and academic research on the partial hydrogenation of polyunsaturated vegetable oils, and of their fatty acids and esters with a wide diversity of prior art selective catalysts until now has failed to directly convert unstable linolenic acid containing oils, such as soybean oil, and other highly unsaturated oils such as safliower oil, into oxidation resistant salad or cooking oils without also converting an intolerably high proportion of the original cis unsaturation to the appreciably higher melting trans configuration, thus necessitating subjecting the partially hydrogenated oil to the losses inherent in a winterization step to remove both the heretofore unavoidable trans components and the high melting saturate (stearate), which is usually also formed during catalytic reductions but not with the herein disclosed arene tricarbonyl chromium oil-soluble catalysts.

A principal object of the instant invention is the provision of a direct process for converting soybean oil or safflower oil into stable, oxidation resistant, refrigeratable salad and cooking oils without a winterization treatment.

A more specific object is the provision of a catalytic hydrogenation process for selectively and very extensively reducing essentially only the linolenate and linoleate constituents of edible oils such as soybean oil and safilower oil or of their mixed methyl esters without increasing the stearic content of the oil by not more than at most about one-half of 1 percent and without sterioisomerizing more than from about 2 percent to not more than about 9.5 percent of the residual unsaturation to the trans configuration, whereby the greatly lowered content of linolenic unsaturation in the resulting low iodine value par- 3,542,821 Patented Nov. 24, 1970 tially hydrogenated oil or ester is about 0 percent to not exceeding about 3 percent without more than negligible, 1f any, increase in stearic acid, thus almost completely preserving the desirable natural all-cis configuration that characterizes the native vegetable oils or the unreduced esters thereof, thereby providing without a winterization step respectively either a low linolenic content, essentially cis liquid oil that can be kept in home refrigerators without clouding or, after saponification of the corresponding ester mixture, and again without winterization, an essentially cis 67-76 percent oleic acid, equivalent to the commercial oleic acids obtained from the carefully fractionated animal fatty acids.

A still more specific object of the invention is the provision of an improved catalytic process for selectively hydrogenatiug polyunsaturated vegetable oils or esters in the presence of certain commercially available arene chromium tricarbonyl complexes that are characterized by being neither so thermostable that they fail to partially dissociate at the operative hydrogenation temperatures, whereby they would be catalytically ineffective, not so thermosensitive that they completely dissociate and thus prematurely terminate the hydrogenation, whereby, when the iodine value (I.V.) shows that the desired extent of hydrogenation has been reached and after the residual catalyst is removed by vacuum stripping or destroyed with ethanolic ferric chloride, the additionally decolorized and deodorized product is a highly stable, essentially cis configuration table oil that does not cloud on refrigeration, or that, if desired, can be saponified to provide a commercial oleic acid.

Other objects and advantages of the invention will be apparent to those skilled in the art from the following detailed description and specific embodiments.

The known commercially available class of arene chromium tricarbonyl complexes, including the herein operative species, whereof the ligands are members selected from the group consisting of the benzene radical and the methyl benzoate radical, are used as gasoline additives and in the manufacture of mirrors and other metallic objects, but they have not heretofore been used as catalysts for the selective hydrogenation of nonconjugated vegetable oil acids and esters.

As reported by the instant applicant and others in Tetrahedron etters 16:1919 (1968) and even more explicitly in Cais and Frankel, Israel patent application entitled Process for the Selective Hydrogenation of Conjugated Double Bonds, filed thereat Aug. 18, 1967, and now in their corresponding US. application S.N. 747,472 filed July 25, 1968, which latter is assignable to the assignee of the instant application, the above arene chromium tricarbonyl complexes were there taught as catalyzing the hydrogenation only of the conjugated but not of the nonconjugated dienes in a fatty acid mixture and of accomplishing the reduction of such predominantly conjugated materials as dehydrated castor oil esters and tung oil without the reduction of the nonconjugated fatty acid constituents, which teachings would make it quite unobvious for one skilled in the art to employ the above catalysts for the selective hydrogenation of nonconjugated vegetable oils such as soybean oil or safliower oil or the mixed fatty esters thereof.

In accordance with the indicated objectives of the invention, I have now discovered that the homogeneous catalytic hydrogenation of an unstable nonconjugated polyunsaturated vegetable oil such as soybean oil for 2-6 hours at about -175 C. in the presence of an arene tricarbonyl chromium complex whereof the ligand is either the benzene radical or the methyl benzoate radical selectively reduces substantially all of the linolenic unsaturation as well as partially hydrogenatiug a substantial portion of the linoleic unsaturation to oleic without causing at most a trivial increase in the saturated fatty acid (stearic) content and most unexpectedly without inducing more than about 3 percent to about 9 percent of trans configuration in the residual double bonds.

The following specific embodiments are intended to more particularly illustrate the invention, but it is understood that various modifications within the spirit of the invention will readily be apparent to one skilled in the art. All of the reactants are understood as being in parts by weight unless otherwise noted.

EXAMPLE 1 A ISO-ml. Magne-Dash high-pressure autoclave equipped with a means for admitting pressurized hydrogen, a heating mantle, a cooling coil, means for controlling and indicating the temperature of the contents, and a magnetic stirrer was charged with 61.4 g. of purified soybean oil having an iodine value of 134.6, the composition of which untreated oil is shown below in Table I.

The autoclave was then flushed with nitrogen, and 0.682 g. of methyl benzoate-chromium tricarbonyl catalyst (1.1% based on the weight of the oil) was introduced.

After being sealed, the autoclave Was purged three times with hydrogen at 500 p.s.i. and then was pressurized to 377 p.s.i. with hydrogen. The heating element was activated, and the oil reached a temperature of 175 C. in 42 min., at which time the pressure had risen to 475 p.s.i. Additional hydrogen was admitted to raise the pressure to 500 p.s.i. which declined to 265 p.s.i. in 1 hour, at which time and at 2 hourly intervals thereafter, the pressure was restored by additions of hydrogen. A sample for analysis was obtained after 2 hours of reaction, and the hydrogenation was terminated at 4 hours by rapidly lowering the temperature.

The tabulated fatty acid values were obtained by GLC after converting an aliquot to mixed methyl esters; the linolenate content was obtained by alkali conjugation; and the extent of trans unsaturation was by infrared spectroscopy. The 4-hour product had ony 0.7 percent linolenate and a 92 percent retention of cis configuration.

Based on the above 4-hour product, the selectivity for linolenate Ivs. linoleate was 2.6:1, and for linoleate vs. oleate the selectivity ratio was calculated as being 250:1.

The selectively hydrogenated 4-hour product contained intact catalyst as shown on infrared analysis by sharp bands at respectively 1985 and 1915 reciprocal cm., and the presence of some decomposed catalyst was also suggested by the impure products dark green color. Although ferric chloride has been used to destroy chromium carbonyl complexes, the complex in this instance was stripped under vacuum, i.e., the residual methyl benzoate chromium tricarbonyl complex was removed by 2 hours of heating at 160-185 C. in a vacuum-assisted rotating evaporator. Although the oil now appeared quite transparent, it still had a greenish cast. The oil was further refined to remove the green coloration by washing with 1.2 percent by weight of phosphoric acid for 45 min., then dissolving in petroleum ether, the ethereal solution being washed with water until the washings were neutral,

4 and then drying with Na SO that was then removed by filtration. The solvent was evaporated under low vacuum. Alternatively, the oil was decolorized and purified by heating on a steam bath for 15 minutes with 10 percent by weight of activated carbon based on the weight of the oil, then dissolving in petroleum ether and filtering after the addition of a commercial diatomaceous earth filter aid. The petroleum ether was removed by water aspirator vacuum, and the light yellow oil was then made almost completely colorless by a conventional deodorization step wherein the oil was subjected to high vacuum (0.25 mm. Hg) while being heated at 190-200 C. for 2 hours. The infrared spectrum of the deodorized selectively hydrogenated oil corresponded to that of the untreated soybean oil excepting for a small trans unsaturation peak at 960 cm.-

EXAMPLE 2 Example 1 was repeated using another batch of soybean oil and on a somewhat larger scale. A 300-ml. autoclave of the same type as used in Example 1 was charged with 200 ml. soybean oil weighing 188.3 g., the composition of which is given in the Untreated column of Table II. Methyl benzoate-chromium tricarbonyl catalyst, 2.09 g., equal to 1.1 percent by weight of the oil was added, and the oil was hydrogenated at 175 C. under a hydrogen pressure of 500 p.s.i. for 6 hours. Samples were taken for analysis during hydrogenation and the pressure was restored to 500 p.s.i. every /2 hour for the first 4 hours and every hour for the remaining 2 hours. Analyses given in Table II show that the selectively hydrogenated oil having a greatly lowered I.V., contained only 0.3-0.5 percent of residual linolenate, and that 33-38 percent of the original diene was reduced to oleate with essentially no increase in stearate, and that 93-94 percent of the residual unsaturation was in the highly desirable cis configuration.

TABLE II Hydrogenated oil, percent Untreated oil, percent 4 hours 6 hours The residual methyl benzoate-chromium tricarbonyl complex was removed as in Example 1 by heating the hydrogenated oil at 162 to 167 C. under 0.3 mm. Hg pressure for 2 hours. The oil was then filtered through fine fritted glass to remove suspended and decomposed catalyst. The oil was then bleached by treating it with 10 percent by weight of carbon black and stirring with nitrogen bubbling on a steam bath for 15 min. The cooled oil was filtered again through fritted glass yielding a clear oil. The catalyst-free bleached oil was conventionally deodorized at 204-214" C. under a vacuum of 0.35-0.45 mm. for 2 hours. The oxidative stability of this oil was tested by the AOM method and compared to the original unhydrogenated soybean oil control which was treated with carbon black and deodorized the same way as the hydrogenated oil. The peroxide value after 8 hours was 13.0 for the hydrogenated oil and 31.3 for the unhydrogenated control oil. We have, therefore, greatly increased the stability of the oil by selective hydrogenation. It required min. of refrigeration at 32 F. for the hydrogenated oil to develop discernible cloudiness. Trace metal analyses by atomic absorption spectra showed that the purified hydrogenated oil contained 0.5 p.p.m. chromium as against a value of 0.8 p.p.m. in the original oil, thus evidencing the effective and complete freedom from residual decomposed catalyst.

A portion of the above hydrogenated oil was saponified with KOH, and the free mixed fatty acids were isolated by conventional means. The following analyses were obtained on this fatty acid product: acid value 200.5; FFA 100.5 percent (calculated as oleic acid); saponification value 191.5; and fatty acid composition as follows: 11.4 percent palmitic; 4.9 percent stearic; 66.7 percent oleic; and 17.0 percent linoleic acid; trans unsaturation 6.6 percent. Although this fatty acid product may be useful industrially, the hydrogenation was not carried out far enough to obtain maximum yields of oleic acids. However, in more extensively hydrogenated Example 10, where it will be noted that the oleic acid content is 75.5 percent, the fatty acid product very closely resembles industrial oleic acid.

EXAMPLE 3 Example 1 was repeated with the exception that 0.53 g. (0.86% by weight of oil) of closely related benzenechromium tricarbonyl catalyst was employed in place of the methyl benzoate-chromium tricarbonyl catalyst of Example 1. The analytical data are presented in Table III.

TAB LE III Hydrogenated oil, percent Example 1 was repeated excepting that only 0.342 g. of methyl benzoate-chromium tricarbonyl catalyst and 62.0 g. oil, i.e., 0.55 percent based on the oil weight was used; also the hydrogenation was not interrupted at 2 hours for a specimen.

An esterified aliquot of the selectively hydrogenated product analyzed 10.3 percent methyl palmitate, 4.1 percent stearate, 37.3 percent oleate, 44.4 percentlinoleate, and 4.1 percent linolenate. It had a trans content of 6.6 percent (i.e., 93.4 percent of the unsaturated bonds were cis), and the calculated I.V. was 119.0. In view of the relatively high residual linolenic level, the product would not be markedly resistant to oxidation, and it is seen that the. above catalyst level is inoperative for applicants purpose.

EXAMPLE 5 Example 4 was repeated excepting that 0.682 g. of methyl benzoate-chromium tricarbonyl, amounting to 1.1 percent based on the oil was employed, and the amount of the soybean oil was slightly less than in Example 4, i.e., 61.4 g.; also the hydrogenation was conducted at a temperature of 165 C. instead of 175 C.; and there was no 2-hour interruption for obtaining a sample. The product when esterified analyzed 10.6 percent palmitate, 4.5 percent stearate, 60.3 percent oleate, 23.8 percent linoleate, and 0.8 percent linolenate. Only 6.8 percent of the unsaturation was trans, and the calculated I.V. was 94.7.

EXAMPLE 6 Example 5 was repeated excepting that the reduction was conducted at 155 C., and for 6 hours instead for 4 hours. An esterified aliquot of the product analyzed 10.2 percent palmitate, 4.1 percent stearate, 58.6 percent oleate, 26.8 percent linoleate, 0.6 linolenate, and only 5.8 percent of the residual unsaturation was trans. The calculated I.V. was 98.0.

EXAMPLE 7 Example 6 was repeated excepting that the reaction was conducted at a temperature of 145 C. An esterified aliquot of the product analyzed 10.2 percent palmitate, 4.0 percent stearate, 46.7 percent oleate, 36.2 percent linoleate, 2.8 percent linolenate, and only 5.5 percent of the residual unsaturation was trans. The calculated I.V. was 109.7.

EXAMPLE 8 A different batch of untreated all-cis soybean oil having an I.V. of 135.8 and, as the mixed methyl esters, analyzing 11.5 percent palmitate, 3.8 percent stearate, 21.1 percent oleate unsaturation, 53.5 percent linoleate, and 9.8 percent linolenate, was obtained for conversion. A 12.25-g. portion of this soybean oil was dissolved in 40 ml. cyclohexane solvent. The same ISO-ml. autoclave used in Examples 1, 3, 4, etc. was charged with the cyclohexane solution, and then flushed with nitrogen before adding 0.169

g. of methyl benzoate-chromium tricarbonyl catalyst corresponding to 1.4 percent based on the weight of the oil. After purging the autoclave three times with hydrogen at 500 p.s.i. and pressurizing with hydrogen to about 375 p.s.i. as described in Example 1, the contents of the autoclave were brought to a temperature of 165 C. at which time additional hydrogen was added to bring the pressure to 500 p.s.i. The reaction was conducted for 6 hours at 165 C. with periodic restorations of pressurized hydrogen.

Instead of removing the residual catalyst by vacuum stripping as in the previous examples, a 6-g. aliquot of the crude product was dissolved in a mixture consisting of 20 ml. percent ethanol, and 30 ml. benzene, contained in a 125ml. Erlenmeyer Flask. The solution was magnetically stirred, and a total of 1.8 of solid FeCl was added in small portions during 30 min. The solution was diluted with water and then extracted three times with petroleum ether. The organic extract was washed three times with water and dried over sodium sulfate. The petroleum ether was removed under vacuum leaving 5.1 g. of clear, colorless oil which by infrared spectroscopy was shown to be free of metal carbonyl complex.

Following esterification of the purified, deodorized aliquot, it analyzed 11.0 percent palmitate, 3.5 percent stearate, 53.6 percent oleate, 30.2 percent linoleate, and 1.6 percent linolenate. Only 3.4 percent of the residual unsaturated bonds were in the trans configuration, and the product had a calculated I.V. of 102.1. It required min. of refrigeration at 0 C. for the oil to develop a discernible cloudiness.

EXAMPLE 9 Example 8 was repeated with the exceptions that only 11.9 g. of the oil was employed, and the amount of the methyl benzoate-chromium tricarbonyl catalyst was increased to 0.342 g. corresponding to 2.9 percent based on the weight of the oil, and the hydrogenation reaction was terminated at 2 hours. Analysis of an esterified aliquot of the purified, deodorized selectively reduced product showed that the constituent fatty esters therein comprised 11.0 percent palmitate, and 4.1 percent stearate, and that it also comprised 57.1 percent oleate, 26.0 percent linoleate, and 1.8 percent linolenate. The extent of trans double bonds was 6.2 percent, and the calculated I.V. of the hydrogenated oil was 98.4.

EXAMPLE 10 Example 9 was repeated with the exception that the hydrogenation reaction was continued for 6 hours instead of 2 hours. Analysis of the mixed methyl esters thereof showed the palmitate content to be 11.2 percent and the stearate to be 4.7 percent. The oleate content was 74.1 percent, the linoleate 10.0 percent, and there was no residual linolenate. The trans unsaturation amounted to 9.5 percent of the residual ethylenic carbons, and the calculated I.V. was 80.6. At 0 C. the cloud point of the oil was 18 min.

An aliquot of the hydrogenated oil was saponified in known manner with ethanolic KOH, and the free fatty acids were isolated by conventional means. The comparison set forth in Table TV shows that the free fatty acids have a composition approximating that of commercial oleic acid.

EXAMPLE 11 Example was repeated with the exceptions that the catalyst was 0.132 g. of benzene-chromium tricarbonyl equivalent to 1.1 percent by weight of the oil instead of the methyl benzoate-chromium tricarbonyl of Example 10, and the hydrogenation reaction was conducted at 175 C. instead of at 165 C.

Analysis of the product in esterified form showed that 11.1 percent of the fatty ester content was palmitate and 3.8 percent was stearate. The oleate comprised 50.9 percent, the linoleate 32.4 percent, and the linolenate 1.8 percent. The trans content of the residual unsaturation was 6 .5 percent, and the calculated I.V. of the hydrogenated oil was 104.2. The zero degree cloud point of the oil was 115 min.

EXAMPLE 12 A 2.265-g. aliquot of soybean oil-derived all-cis mixed methyl esters analyzing 10.3 percent palmitate, 4.5 percent stearate, 26.6 percent oleate, 50.2 percent linoleate, and 8.4 percent linolenate, and having an I.V. of 131.0 was dissolved in cyclohexane. The solution was transferred to the previously described 150-ml. autoclave. The autoclave was then flushed with nitrogen and 0.0575 g. of methyl benzoate-chromium tricarbonyl equivalent to 2.5 percent by weight of mixed esters was introduced. The autoclave was then pressurized with hydrogen as previously described and heated to 165 C. The ester solution was hydrogenated for 6 hours. The residual catalyst in the crude product was decomposed with a 95 percent ethanol solution of FeCl;; and then removed in the previously described manner.

Analyses of the selectively hydrogenated soybean mixed methyl ester product showed it to be 10.4 percent palmitate, 4.8 percent stearate, 30.8 percent oleate, 48.3 percent linoleate, and 5.2 percent linolenate. Only 3.5 percent of the residual double bonds were in the trans configuration. The calculated I.V. was 123.9. The linolenate/ linoleate hydrogenation selectivity value of the catalyst was 5.1:1, and the linoleate/oleate selectivity ratio was 6.8: 1. Since both the linolenate and iodine values are too high, it is clear that insufficient catalyst was used.

EXAMPLE 13 Example 12 was repeated with the exceptions that the amount of catalyst was doubled so as to provide a 5.0 percent level, and the hydrogenation temperature was increased to 175 C. The residual catalyst was removed as in the preceding example, and the purified ester mixture analyzed 10.3 percent palmitate, 4.7 percent stearate, 67.0 percent oleate, and 18.0 percent linoleate. Only 7.3 percent of the residual unsaturation was trans, and the calculated I.V. of the product was 88.4. Hydrolysis of the above product obviously would provide a mixture consisting almost exclusively of cis fatty acids wherein the resulting oleic acid content of 67 percent would conform to that of some brands of commercial oleic acid. It may be pointed out that when only half as much catalyst was used at 175 C., the methyl oleate content was only 50.2 percent.

EXAMPLE 14 Saffiower oil was selectively hydrogenated with methyl benzoate-chromium tricarbonyl catalyst in the previously described 150-ml. autoclave. A 32.7-g. portion of a refined but not deodorized safflower oil analyzing in esterified form 6.3 percent palmitate, 2.3 percent stearate, 11.6 percent oleate, and 79.8 percent linoleate, and having a calculated I.V. of 147 was mixed with 0.819 g. of methyl benzoate-chromium tricarbonyl equivalent to 2.5 percent catalyst by weight of the oil. The mixture was purged with hydrogen and heated to 175 C. at hourly 500 p.s.i.- restored hydrogen pressure for 6 hours. The hydrogenated product in ester form analyzed 6.0 percent palmitate, 2.4 percent stearate, 44.6 percent oleate, and 47.0 percent linoleate, and had a calculated I.V. of 119. The trans unsaturation content was only 4.4 percent.

When the amount of catalyst was doubled under otherwise identical conditions, the product corresponded to 5.9 percent palmitate, 2.9 percent stearate, 57.1 percent oleate, and 34.1 percent linoleate. The trans unsaturation content was only 4.5 percent, and the calculated I.V. was 108.

EXAMPLE 15 The hydrogenation of another batch of especially fresh safllower oil which had been refined and deodorized proceeded more rapidly and to a higher level than occurred in Example 14. A 38.0-g. portion of this safilower oil, which in esterified form analyzed 7.3 percent palmitate, 2.9 percent stearate, 14.4 percent oleate, 75.6 percent linoleate, and had a calculated I.V. of 142, was hydrogenated in the persence of 1.00 g. methyl benzoate-chromium tricarbonyl, representing 2.6 percent by weight of the oil, under the same conditions as in Example 14 with the exception that the reaction time was 1.5 hours instead of 6 hours. Analysis of the methyl esters produced from the product showed 6.3 percent palmitate, 3.2 percent stearate, 73.6 percent oleate, and 17.0 percent linoleate. The trans unsaturation content was 8.9 percent and the calculated I.V. was 92.3.

The hydrogenated oil product was saponified and the free fatty acids were isolated by conventional means. Analysis of the free fatty product showed: acid value 197.7; FFA 99.6 percent (calculated as oleic acid); saponification value 196; fatty acid composition: 6.9 percentpalmitic, 2.8 percent stearic, 72.6 percent oleic, and 17.7 percent linoleic acid; calculated I.V. of 92.7.

The refined bleached, and deodorized soybean oils hydrogenated to I.V.s ranging between and and the safliower oils hydrogenated to an I.V. of 108 to 119 produced by the catalytic process of this invention may be used as stable, refrigeratable salad oils. The free fatty acids prodced by saponification of these oils hydrogenated to an I.V. of about 90 or below will meet the specifications of commercial oleic acid, which is widely used for soaps and detergents, cosmetics and toiletries, polishes and cleaners, lubricants for synthetic rubber polymerization, surface coatings, plasticizers, flotation, and various other well-known purposes.

I claim:

1. In a process for selectively hydrogenating a vegetable oil material selected from the group consisting of soybean oil, safflower oil, and the mixed methyl esters thereof at an elevated temperature and in the presence of a catalyst, the improvement comprising the steps of conducting the hydrogenation for 1.5-6 hours at -175 C. at periodically restored hydrogen pressures of about 500 p.s.i. in the presence of from 0.9-5.0 percent based on the weight of the oil material of an oil-soluble organometallic catalyst selected from the group consisting of benzene-chromium tricarbonyl and methyl benzoate-chromium tricarbonyl, then freeing the thusly hydrogenated material of residual catalyst by stripping under vacuum or by reaction with ethanolic ferric chloride solution, and purifying the resulting material by conventional decolorization and deodorization procedures whereby to obtain a product wherein at least 90-91 percent of the residual unsaturation is retained in the cis configuration and wherein the thereby obtained hydrogenated soybean oil members are further characterized by a linolenic acid content not exceeding about 2.8 percent, an I.V. of 95-110, a stearic acid content of 4.1-4.7 percent, and by a high resistance to clouding at household refrigeration temperatures and wherein the hydrogenated safilower oil members are further characterized by an I.V. of 92-119, an oleic acid content of 44.6-73.6 percent, a residual unsaturation whereof at least about 91 percent is in the cis configuration, and by a high resistance to clouding at household refrigeration temperatures.

2. In the improved process as defined in claim 1 wherein the said oil material is safllower oil, the catalyst is methyl benzoate-chromium tricarbonyl that is present in an amount corresponding to 2.6 percent by weight of the oil, and wherein the hydrogenation is conducted at 175 C. for 1.5 hours in the presence of said catalyst to provide a selectively hydrogenated oil characterized by an I.V. of about 92, by residual unsaturation of which 91 percent had remained in the cis configuration, and by the presence of steps of saponifying the so-produced oil and recovering the mixed fatty acids therefrom.

3. In the improved process as defined in claim 1 wherein the said oil material is soybean oil, the catalyst is methyl benzoate-chromium tricarbonyl that is present in an amount corresponding to 2.9 percent by weight of the oil, and wherein the hydrogenation is conducted at 165 C. for 6 hours in the presence of said catalyst to provide a selectively hydrogenated oil characterized by an iodine value of 80.6, by residual unsaturation of which 90.5 percent had remained in the cis configuration, and by the presence of about 75.5 percent of constituent oleic acid, the further steps of saponifying the so-produced oil, and recovering the mixed fatty acids therefrom.

References Cited UNITED STATES PATENTS 1/1968 Whiting 260438.5 l/ 1968 Cofiield et al. 260-429 OTHER REFERENCES LEWIS GOTTS, Primary Examiner about 67-72 percent of constituent oleic acid, the further C. L. MILLS, Assistant Examiner 

